The Collapse of “Galloping Gertie”

The Tacoma Narrows Bridge, nicknamed “Galloping Gertie” by the locals because of its intense sway in heavy winds, was a bridge in Washington that collapsed after just 4 months.

It was initially designed to be more stable, with trusses, or a series of structural triangles for support, that were 25 feet high. The only problem is that it would cost $11 million. Another engineer came along and proposed a much less stable design with plate girders, but it cost only $8 million, and that design won. Nowadays, when designing bridges in windy areas, engineers stray away from plate girders because of this catastrophe. Girders catch wind, while trusses allow wind to pass between the structural triangle shaped supports.

Even during construction, the bridge was being moved significantly by the wind, and after it opened, workers attempted to reinforce the bridge with cables but the wind snapped those. In addition to it bouncing up and down in the wind, especially strong winds caused it to twist. This twisting would be its downfall. On November 7^th, 1940, “Galloping Gertie” had one last gallop as its cables snapped and several hundred feet of the bridge crumbled into the river below.

The lessons here are don’t be cheap and do research and tests before building a bridge. Spend the necessary money to build the best product, especially when this product is being used by human beings. Also, the Washington Toll Bridge Authority brought an engineering professor in to perform wind tunnel tests after the bridge was built. These tests should be done beforehand, so the most ideal bridge can be built.

Works Cited:

American Physical Society. “November 7, 1940: Collapse of the Tacoma Narrows Bridge.” APS News, 1 Nov. 2016. https://www.aps.org/archives/publications/apsnews/201611/physicshistory.cfm